Scientists have found the unlikeliest source for research about space weather: Cold War history.

The United States and the Soviet Union conducted a series of high-altitude nuclear tests between 1958 and 1962. Government data about the tests was unavailable for a long time, but was recently declassified, and has now illuminated links between the trial explosions and disruptions in Earth’s magnetic environment.

“The tests were a human-generated and extreme example of some of the space weather effects frequently caused by the sun,” Phil Erickson, a co-author of the new study, told NASA. Normally the sun creates space weather by shooting out charged particles as what we call “solar wind.” Earth’s magnetic field diverts most of this wind, but when particles do make it inside, they can damage satellites, create auroras, and even incite currents that impair power grids.

The nuclear tests undertaken during the Cold War caused similar geomagnetic disturbances. Just like the sun, the bombs — which detonated between 16 and 250 miles above the ground — shot out charged particles in the fiery gas expelled by the initial blast waves.

Some tests created artificial radiation belts. The Teak test of 1958 caused an aurora over the equator (normally, they’re only seen at the poles); the Argus tests of the same year created extremely short and fast geomagnetic storms. Others affected satellites and utility grids.

NASA Space Weather
Radiation belts, in a diagram provided by NASA (artificial belts imagined in yellow).

Humans no longer conduct nuclear tests in the atmosphere, so we shouldn’t experience any other artificial causes of these phenomena. But it’s extremely useful to study these past cases because they provide extreme and sudden examples of shifts in space weather, which often happen more subtly.

“If we understand what happened in the somewhat controlled and extreme event that was caused by one of these man-made events,” says Erickson. “We can more easily understand the natural variation in the near-space environment.”

NASA’s press release on the study says that the new data about these phenomena will help “support NASA’s efforts to protect satellites and astronauts from the natural radiation inherent in space.”

Photos via NASA Goddard